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Abstract:

A gas-to-liquids process and plant for treating natural gas, in which the
natural gas is subjected to expansion through a flow restrictor so as to
undergo cooling through the Joule Thomson effect, enables liquids to be
separated from the gas stream. The natural gas may be cooled before it
reaches the flow restrictor by heat exchange with fluid that has passed
through the flow restrictor. This decreases the proportion of
longer-chain hydrocarbons in the natural gas, which may simplify
subsequent processing, and may enable the size of the plant to be
decreased.

Claims:

1-19. (canceled)

20. A gas-to-liquids plant for treating natural gas, wherein the natural
gas is subjected to expansion through a flow restrictor so as to undergo
cooling through the Joule Thomson effect, with separation of resulting
longer-chain hydrocarbon liquid from remaining natural gas, wherein the
plant further comprises means to process the remaining natural gas to
form a synthesis gas, and a Fischer-Tropsch reactor to which the
synthesis gas is provided, and means to separate hydrocarbon product and
aqueous phase from the output of the Fischer-Tropsch reactor, and means
for separating oxygenates from the aqueous phase and means to introduce
the oxygenates into the natural gas stream upstream of the flow
restrictor.

21. A plant as claimed in claim 20 comprising a heat exchanger arranged
for heat transfer between the natural gas before it reaches the flow
restrictor, and at least one fluid that has been cooled by passage
through the flow restrictor.

22. A plant as claimed in claim 20 wherein the synthesis gas formation
means forms a synthesis gas containing excess hydrogen, and wherein the
plant further comprises a separator to remove hydrogen from the synthesis
gas.

23. A plant as claimed in claim 22 including a fuel header to which
separated hydrogen is supplied.

24. A plant as claimed in claim 23 wherein the synthesis gas formation
means is adapted to use an endothermic reaction, wherein heat for the
reaction is provided at least in part by combustion of fuel from the fuel
header.

25. A plant as claimed in claim 20 comprising means to separate tail gas
from the output from the Fischer-Tropsch reactor, wherein some of the
tail gas is recirculated into the synthesis gas stream, and some of the
tail gas is fed into the fuel header.

26. A plant as claimed in claim 20 also comprising a heat exchanger
whereby at least some of the heat produced by the Fischer-Tropsch
reaction is used to generate steam, and wherein the steam is combined
with an air stream for a combustion process.

27. A plant as claimed in claim 20 comprising a steam stripper to
separate the oxygenates from the aqueous phase.

28. A gas-to-liquids process for treating natural gas, including the
steps of subjecting the natural gas to expansion through a flow
restrictor so as to undergo cooling through the Joule Thomson effect,
followed by separating the resulting longer-chain hydrocarbon liquid from
the remaining natural gas, further comprising the steps of processing the
natural gas to form a synthesis gas, and subjecting the synthesis gas to
Fischer-Tropsch synthesis, and wherein the output from the
Fischer-Tropsch synthesis is separated into a hydrocarbon product and an
aqueous phase, wherein the aqueous phase is treated to extract the
oxygenates which are then injected into the natural gas stream upstream
of the flow restrictor.

29. A process as claimed in claim 28 including the step of transferring
heat between the natural gas before it reaches the flow restrictor, and
at least one fluid that has been cooled by passage through the flow
restrictor.

30. A process as claimed in claim 28 wherein the step of processing the
natural gas to form a synthesis gas results in a synthesis gas containing
excess hydrogen, and further comprising the step of removing excess
hydrogen from the synthesis gas.

31. A process as claimed in claim 30 wherein the synthesis gas formation
process uses an endothermic reaction, wherein the process comprises the
step of providing heat for the endothermic reaction at least in part by
combustion of the removed excess hydrogen.

32. A process as claimed in claim 28, wherein a tail gas is separated
from the output from the Fischer-Tropsch synthesis, and wherein some of
the tail gas is recirculated into the synthesis gas stream, and some of
the tail gas is used as a fuel.

33. A process as claimed in claim 28 wherein at least some of the heat
produced by the Fischer-Tropsch reaction is used to generate steam, and
wherein the steam is combined with an air stream for a combustion
process.

34. A process as claimed in claim 31 wherein an air stream for combustion
is preheated by mixing with hydrogen from the removed excess hydrogen,
and passing through a catalytic structure comprising an
aluminium-containing ferritic steel without any catalytic coating, so
that the hydrogen undergoes catalytic combustion at the surface of the
steel.

36. A gas-to-liquids plant for treating natural gas, wherein the natural
gas is subjected to a single stage expansion through a flow restrictor so
as to undergo cooling through the Joule Thomson effect, with separation
of resulting longer-chain hydrocarbon liquid from remaining natural gas.

37. A gas-to-liquid process for treating natural gas, including the step
of subjecting the natural gas to a single expansion through a flow
restrictor so as to undergo cooling through the Joule Thomson effect,
followed by separating the resulting longer-chain hydrocarbon liquid from
the remaining natural gas.

Description:

[0001] The present invention relates to a plant and a process for treating
natural gas to produce a liquid product.

[0002] It is well known that most oil wells also produce natural gas. At
many oil wells natural gas is produced in relatively small quantities
along with the oil. When the quantities of this associated gas are
sufficiently large or the well is close to pre-existing gas
transportation infrastructure, the gas can be transported to an off-site
processing facility. When oil production takes place in more remote
places it is difficult to introduce the associated gas into existing gas
transportation infrastructure. In the absence of such infrastructure, the
associated gas has typically been disposed of by flaring or re-injection.
However, flaring the gas is no longer an environmentally acceptable
approach, while re-injection can have a negative impact on the quality of
the oil production from the field.

[0003] Gas-to-liquids technology can be used to convert the natural gas
into liquid hydrocarbons and may follow a two-stage approach to
hydrocarbon liquid production comprising syngas generation, followed by
Fischer-Tropsch synthesis. In general, syngas (a mixture of hydrogen and
carbon monoxide) may be generated by one or more of partial oxidation,
auto-thermal reforming, or steam methane reforming. Where steam methane
reforming is used, the reaction is endothermic and so requires heat. The
syngas is then subjected to Fischer-Tropsch synthesis. For performing
Fischer-Tropsch synthesis the optimum ratio of hydrogen to carbon
monoxide is about 2:1, and steam reforming has a benefit of providing
more than sufficient hydrogen for this purpose.

[0004] Such a process is described for example in WO 01/51194 (AEA
Technology) and WO 03/006149 (Accentus plc). Natural gas is primarily
methane, but also contains small proportions of longer-chain
hydrocarbons. In each case the natural gas is first subjected to a
pre-reforming step in which the longer-chain hydrocarbons are converted
to methane by reaction with steam, for example over a nickel catalyst at
400° C. As regards the Fischer-Tropsch process, as described in WO
2004/050799 (GTL Microsystems AG), a suitable catalyst uses small
particles of cobalt on a ceramic support, but this catalyst can suffer a
deleterious reaction in the presence of water vapour. To ensure this does
not occur the reactor is operated so as to ensure the Fischer-Tropsch
conversion is no more than 70%, and then the resulting gases are
subjected to a second Fischer-Tropsch stage. Although this provides a
satisfactory way of converting natural gas to a longer-chain hydrocarbon
product, it would be desirable to provide an alternative plant and
process.

[0005] According to the present invention there is provided a
gas-to-liquids plant for treating natural gas, wherein the natural gas is
subjected to expansion through a flow restrictor so as to undergo cooling
through the Joule Thomson effect, with separation of resulting liquids.

[0006] The present invention also provides a process for treating natural
gas in this way. The process of the invention relates to a chemical
process for converting natural gas (primarily methane) to longer chain
hydrocarbons.

[0007] Ideally the expansion takes place without significant transfer of
heat from the surroundings, the natural gas expanding into a lower
pressure state. The flow restrictor may be a throttle valve, or
alternatively may be an inlet nozzle of a vortex tube separator, or a
turbo expander, or a Twister® separator device. A vortex tube, or
Ranque-Hilsch tube, splits the gas into a hot gas stream and a cold gas
stream. The hot gas stream may be utilised elsewhere within the plant.
However, as a result of the division into two streams, only a proportion
of the gases are cooled. The expansion can cool the natural gas to below
0° C., more particularly below -10° C. for example below
-15° C., with the consequence that longer-chain hydrocarbons
condense from the vapour state into the liquid state, and can be
separated from the remaining natural gas. The degree of cooling is
selected to ensure that the output stream is at a pressure sufficient to
drive gas through the process. Whilst the temperature can be dropped
further in order to increase the recovery of higher hydrocarbons, this
ceases to be advantageous when the cost of the increased compression
requirements to re-pressurize the gas exceed the value of the additional
longer chain hydrocarbons recovered. Preferably the natural gas stream is
fed into the flow restrictor through a heat exchanger in which it is
cooled by contact with at least one fluid that has been cooled by passage
through the flow restrictor, so that the natural gas is below ambient
temperature when it reaches the flow restrictor.

[0008] A benefit of this process is that the proportion of longer-chain
hydrocarbons in the remaining natural gas is considerably reduced. It may
therefore be practicable to then subject the natural gas to reforming
without the need for a separate pre-reformer. A further benefit is that
the quantity of hydrocarbons subjected to the subsequent chemical
processes is reduced, which may reduce the size and hence the cost of the
remainder of the plant.

[0009] A potential problem in such a cooling process is the risk of
formation of methane-containing hydrates, although this may not be an
issue with a Twister device as the residence time may be sufficiently
short to prevent formation of hydrate crystals. To address this issue,
oxygenates such as methanol or ethanol may be introduced into the natural
gas stream upstream of the flow restrictor. These prevent the formation
of hydrates. In the context of a gas-to-liquid plant, such oxygenates are
produced during the Fischer-Tropsch synthesis, and can be extracted from
the resulting aqueous phase by steam stripping. These oxygenates hence
allow the gas stream to be cooled to a lower temperature. The natural gas
is then converted to synthesis gas either by steam methane reforming,
partial oxidation or auto-thermal reforming. In the case of steam methane
reforming, the requisite heat may be provided by catalytic combustion
within adjacent channels within an integrated reforming/combustion
reactor, or by hot exhaust gases from a separate combustion reactor. The
resulting synthesis gas contains more hydrogen than is required for
Fischer-Tropsch synthesis, and at least some excess hydrogen may be
separated from the synthesis gas by a membrane separator, and supplied to
a fuel header. If a membrane is not used for separation, separation can
be performed by pressure swing absorption. The fuel header may supply the
fuel for the combustion process that provides the heat for the steam
methane reforming reaction, or may provide fuel for preheating an air
supply for such a combustion process.

[0010] The synthesis gas may then be subjected to a Fischer-Tropsch
synthesis reaction to convert the synthesis gas into longer chain
hydrocarbons. This may be a single stage process or a two-stage process.
After separating liquid hydrocarbon product and an aqueous phase, for
example in a tubular heat exchanger followed by separation by density
differences in a vessel, there is a resulting tail gas. The tail gas
contains hydrogen, carbon monoxide, carbon dioxide and methane. Some of
the tail gas is preferably fed into the synthesis gas stream, preferably
upstream of the membrane separator. At least some of the tail gas is fed
into the fuel header.

[0011] At least some of the aqueous phase may be boiled to produce a steam
and oxygenate-containing vapour, which is fed into the combustion gas
mixture. For example it may be fed into a stream of combustion air
supplied to combustion channels or to a combustion reactor.

[0012] It will be appreciated that the steam/methane reforming process
produces two hot out-flowing streams: a synthesis gas stream typically at
above 800° C., and an exhaust gases stream which may be at a
similar temperature (if an integrated combustion/reforming reactor is
used) or which may be at a somewhat lower temperature (if a separate
combustion reactor is used). Preferably these hot streams are used to
provide thermal energy to gases being supplied to the reforming process.
For example the hot synthesis gas may be used to provide the steam
required for reforming, while the exhaust gases may be used to preheat
combustion air.

[0013] In a further aspect of the present invention there is provided a
gas-to-liquid process, and a plant to perform the process, wherein the
process utilises a combustion step using a stream of air, and wherein the
process produces excess hydrogen, wherein excess hydrogen is separated
using a membrane or using pressure swing absorption, and is used to
preheat the combustion air stream. The preheating of the air stream may
utilise a catalytic combustion process. For example the hydrogen may be
separated from a synthesis gas or from a tail gas of a Fischer-Tropsch
synthesis reaction.

[0014] In yet a further aspect the present invention provides a
gas-to-liquid process, and a plant to perform the process, wherein the
process utilises a combustion step, and where the process performs
Fischer-Tropsch synthesis, wherein heat from the Fischer-Tropsch
synthesis is used to generate steam, and the steam is introduced into a
gas stream supplied to the combustion step. The steam that is supplied to
the combustion step may include oxygenates that are produced as a
byproduct of the Fischer-Tropsch synthesis.

[0015] The invention will now be further and more particularly described,
by way of example only, and with reference to the accompanying drawing
which shows a schematic flow diagram of a gas-to-liquid plant and
associated equipment.

[0016] The invention relates to a chemical process for converting natural
gas (primarily methane) to longer chain hydrocarbons. It is suitable for
treating associated gas, which is natural gas that is produced along with
crude oil, and is then separated from the crude oil. The first stage of
the chemical process involves the formation of synthesis gas, for example
by steam reforming, by a reaction of the type:

H2O+CH4→CO+3 H2 (1)

[0017] This reaction is endothermic, and may be catalysed by a rhodium or
platinum/rhodium catalyst in a first gas flow channel. The heat required
to cause this reaction may be provided by catalytic combustion of a gas
such as methane or hydrogen, which is exothermic, in an adjacent channel,
or by heat exchange with exhaust gases from a separate combustion
reactor. The combustion may be catalysed by a palladium catalyst in an
adjacent second gas flow channel in a compact catalytic reactor. In both
cases the catalyst may be on a stabilised-alumina support which forms a
coating typically less than 100 μm thick on a metallic substrate.
Alternatively, the catalyst may be applied to the walls of the flow
channels or may be provided as pellets within the flow channel. The heat
generated by the combustion would be conducted through the metal sheet
separating the adjacent channels.

[0018] The gas mixture produced by the steam/methane reforming is then
used to perform a Fischer-Tropsch synthesis to generate a longer chain
hydrocarbon, that is to say:

n CO+2n H2→(CH2)nn H2O (2)

which is an exothermic reaction, occurring at an elevated temperature,
typically between 190° C. and 280° C., for
example230° C., and an elevated pressure typically between 1.8 MPa
and 2.6 MPa (absolute values), for example 2.5 MPa, in the presence of a
catalyst such as iron, cobalt or fused magnetite, with a potassium
promoter. Whilst Fe based catalysts can be used, metallic Co promoted
with precious metals such as Pd, Pt, Ru or Re doped to 1 wt % are
preferred when operating at lower temperatures as they have enhanced
stability to oxidation. The active metals are impregnated to 10-40 wt %
into refractory support materials such as TiO2, Al2O3 or
SiO2 which may be doped with rare earth and transition metal oxides
to improve their hydrothermal stability.

1. Pre-Treatment

[0019] Referring to FIG. 1, there is shown a gas-to-liquid plant 10 of the
invention. A natural gas feed 5 consists primarily of methane, but with
small proportions of other gaseous hydrocarbons, hydrocarbon vapours, and
water vapour. The gas feed 5 may for example be at a pressure of 4.0 MPa
(40 atmospheres) and 35° C., following sea water cooling from an
initial temperature of 90° C., and may constitute associated gas
from a well producing crude oil. The natural gas feed 5 is first passed
through a coalescer 12 which removes any droplets. A small quantity of
oxygenates (primarily ethanol and methanol, and marked "alcohol") is then
sprayed into the gas feed 5 at an injector 14, and the gas feed 5 is then
passed through a heat exchanger 15 to cool it, and then through a
throttle valve 16 through which it expands into a lower pressure region
(typically at about 1 MPa) adiabatically, with no significant heat input
from the surroundings. Consequently, in accordance with the Joule Thomson
effect, the natural gas is considerably cooled, for example to
-18° C. The resulting cooled stream is then fed into a phase
separator 18, so producing a gas phase 20, a liquid hydrocarbon phase 21,
and an aqueous phase 22 (containing the oxygenates). The use of the
oxygenates ensures that methane-containing hydrates are not produced. All
three of these fluids streams are passed through the heat exchanger 15 so
as to cool the in-flowing gas feed 5.

[0020] The liquid hydrocarbon phase 21 constitutes part of the product
output stream of liquid hydrocarbon from the plant 10.

[0021] The gas phase 20 is then subjected to pretreatment 25, which may
comprise one or more of the following: changing its pressure; changing
its temperature; and removing impurities such as sulphur. It is then
mixed with steam in a mixer 26.

2. Making Synthesis Gas

[0022] The gas/steam mixture, preferably at a temperature of about
450° C., is then fed into a catalytic steam/methane reformer 30.
The reformer 30 consists of a compact catalytic reactor formed from a
stack of plates defining two sets of channels arranged alternately. One
set of channels are for the reforming reaction, and contain a reforming
catalyst on removable corrugated metal foil supports, while the other set
of channels are for the provision of heat.

[0023] In this example the heat is provided using a separate burner 32,
the exhaust gases from the burner 32 at about 850° C. being passed
through the reformer 30 in counter-current to the flow of the
steam/methane mixture. The reaction channels of the reformer 30 may
contain a nickel catalyst in an initial part of the channel, of length
between 100 and 200 mm, for example 150 mm, out of a total reaction
channel length of 600 mm. In the first part of the channel, where the
nickel catalyst is present, pre-reforming takes place, so any higher
hydrocarbons will react with steam to produce methane. The remainder of
the length of the reaction channels contains a reformer catalyst, for
example a platinum/rhodium catalyst, where the steam and methane react to
form carbon monoxide and hydrogen.

[0024] The heat for the steam/methane reforming reaction in the reformer
30 is provided by combustion of a fuel gas from a fuel header 34 in a
stream of combustion air. In this example the fuel gas is primarily
hydrogen. The combustion air is provided by a blower 36 and is preheated
in a heat exchanger 38, taking heat from the hot exhaust gases from the
combustion after they have passed through the reformer 30. In addition a
mixture of steam and alcohol vapour 40 is introduced into the combustion
air upstream of the burner 32. After passing through the heat exchanger
38 the exhaust gases may be vented through a stack 39.

[0025] A mixture of carbon monoxide and hydrogen at above 800° C.
emerges from the reformer 30, and is quenched to below 400° C. by
passing it through a steam-raising heat exchanger 42 in the form of a
thermosiphon. The heat exchanger 42 is a tube and shell heat exchanger,
the hot gases passing through the tubes, and with inlet and outlet ducts
communicating with the shell at the top and bottom, and communicating
with a steam drum 44. The steam drum 44 is about half full of water, and
so water circulates through natural convection between the heat exchanger
42 and the steam drum 44. The resulting steam from the steam drum 44 is
supplied to the mixer 26 through a control valve 46.

[0026] The gas mixture, which is a form of synthesis gas, may be subjected
to further cooling (not shown). It is then subjected to compression using
two successive compressors 50, preferably with cooling and
liquid-separation stages (not shown) after each compressor 50. The
compressors 50 raise the pressure to about 2.5 MPa (25 atm).

[0027] It will be appreciated from equation (1) above that the ratio of
hydrogen to CO produced in this way is about 3:1, whereas the
stoichiometric requirement is about 2:1, as is evident from equation (2).
The high-pressure synthesis gas is therefore passed by a
hydrogen-permeable membrane 52 to remove excess hydrogen. This hydrogen
is supplied to the fuel header 34, and is the principal fuel gas.

3. Fischer-Tropsch Synthesis And Product Treatment

[0028] The stream of high pressure carbon monoxide and hydrogen is then
heated to about 200° C. in a heat exchanger 54, and then fed to a
catalytic Fischer-Tropsch reactor 55, this again being a compact
catalytic reactor formed from a stack of plates as described above; the
reactant mixture flows through one set of channels, while a coolant flows
through the other set. The coolant is circulated by a pump 56 and through
a heat exchanger 58. The Fischer-Tropsch reaction takes place at about
210° C., and the coolant is circulated at such a rate that the
temperature varies by less than 10 K on passage through the reactor 55.

[0029] The reaction products from the Fischer-Tropsch synthesis,
predominantly water and hydrocarbons such as paraffins, are cooled to
about 70° C. to condense the liquids by passage through a heat
exchanger 60 and fed to a separating chamber 62 in which the three phases
water, hydrocarbons and tail gases separate. The aqueous phase contains
water with about 1-2% oxygenates such as ethanol and methanol which are
formed by the Fischer-Tropsch synthesis. Most of the aqueous phase from
the separating chamber 62 is treated by steam stripping 63 to separate
the oxygenates (marked "alcohol") to leave clean water that may be
discharged to waste. The separated oxygenates, which are at an oxygenate
concentration of about 80%, are injected into the injector 14 upstream of
the throttle valve 16 as described above. The remainder of the aqueous
phase is fed as process water through the heat exchanger 58, and hence
through a pressure-drop valve 64 into a stripper tank 66. In the stripper
tank 66 the aqueous phase boils, typically at a pressure of about 1.0 MPa
(10 atm), the liquid phase being fed from the bottom of the stripper tank
66 into the steam drum 44, while the vapour phase, which contains steam
and the bulk of the oxygenates, provides the stream 40 that is introduced
into the combustion air through a control valve 68.

[0030] The hydrocarbon phase from the separating chamber 62 is the
longer-chain hydrocarbon product. The vapour and gas phase from the
separating chamber 62 is fed through two successive cooling heat
exchangers 70, the second of which cools the vapours to ambient
temperature. Any liquids that condense on passage through the first heat
exchanger 70 are fed back into the separating chamber 62. The output from
the second heat exchanger 70 is fed into a phase separating chamber 72,
where the water and light hydrocarbon product liquid separate.

[0031] The remaining vapour phase, which is at the same pressure as the
Fischer-Tropsch reactor 55, is then passed through a heat exchanger 74 to
a throttle valve 76 followed by a phase separating vessel 78. As the gas
passes through the throttle valve 76 it expands into a lower pressure
region adiabatically, with no significant heat input from the
surroundings. Consequently, in accordance with the Joule Thomson effect,
the gas is cooled considerably. The liquids that emerge from the phase
separating pressure 78 contain water and light hydrocarbon product. The
gases that emerge from the phase separating vessel 78, which are the tail
gases from the Fischer-Tropsch process, are passed back through the heat
exchanger 74 to cool the in-flowing gases and, optionally, through a
hydrogen permeable membrane (not shown). Part of the tail gas may be fed
back into the synthesis gas stream upstream of the first compressor 50.
At least part of the tail gas is fed into the fuel header 34, to ensure
that there is no excessive build-up of methane in the Fischer-Tropsch
reactor 55.

4. Energy Transfer And Process Review

[0032] The fuel header 34 not only provides the fuel for the burner 32,
but also supplies fuel via a fuel compressor 80 to a gas turbine 82.
Indeed compressed fuel gas may also be supplied to other equipment (not
shown) that does not form part of the plant 10. The gas turbine 82 may be
arranged to provide electrical power for operating the plant 10. As
indicated by a broken line in the figure, in this example the electrical
power generated by the gas turbine 82 is used to power the compressors
50. Alternatively the gas turbine 82 may be coupled directly to drive the
compressors 50.

[0033] It will be appreciated that in the above-described process the heat
produced by the Fischer-Tropsch reaction is used in boiling steam and
alcohol in the stripper tank 66, and so is transferred to the combustion
channels by the feed 40. The remaining heat required for reforming is
provided by the fuel gas from the fuel header 34 undergoing combustion in
the burner 32. This may be a duct burner, in which there are several
nozzles through which fuel gas is fed into a stream of combustion air, so
it burns with a flame. Alternatively the burner 32 may be a catalytic
flame-less combustion unit. As previously mentioned, the resulting hot
exhaust gas supplies heat to the reformer 30, and is then used to preheat
combustion air in the heat exchanger 38.

[0034] In a modification to the above-described process the combustion air
may be additionally pre-heated by introducing hydrogen into the
combustion air, and passing it through a honeycomb structure of an
aluminium-containing ferritic steel such as Fecralloy, with an oxidised
surface, which has been found to be a catalytic to hydrogen combustion.
Alternatively the preheating may be performed using a duct burner in
which a fuel such as hydrogen is burnt. The final heating of the
combustion air to the desired temperature in the vicinity of 800°
C. may then be achieved using a duct burner 32 to which a combustible gas
stream is provided, such as the tail gas from the Fischer-Tropsch
process, or as described above using a burner 32 which is a catalytic
flame-less combustion unit.

[0035] In a further modification, the combustion air is preheated either
by passage through a duct burner provided with a suitable fuel, or by
introducing hydrogen into the combustion air, and passing it through a
honeycomb structure of aluminium-containing ferritic steel as described
above, so that hydrogen undergoes catalytic combustion. The hot
combustion air is then fed into an integrated combustion/reforming
reactor, and a fuel such as methane or tail gas is introduced and
subjected to catalytic combustion in the heat-providing channels of the
reactor through which the hot combustion air flows. In this modification
the catalytic combustion may, for example, take place over a
palladium/platinum catalyst within the heat-providing channels within the
reforming reactor 30. In this case the combustion gas path is preferably
co-current relative to the reformer gas path. The catalyst may include
gamma-alumina as a support, coated with a palladium/platinum 3:1 mixture,
which is an effective catalyst over a wide temperature range. The
combustible gas mixture may be supplied in stages along the reactor 30 to
ensure combustion occurs throughout the length of the combustion
channels.

Patent applications by David James West, Ducklington GB

Patent applications by Michael Joseph Bowe, Preston GB

Patent applications by Philip Hawker, County Kerry IE

Patent applications by Robert Peat, Longcot GB

Patent applications by CompactGTL plc

Patent applications in class WITH PRELIMINARY REACTION TO FORM HYDROGEN OR A CARBON OXIDE

Patent applications in all subclasses WITH PRELIMINARY REACTION TO FORM HYDROGEN OR A CARBON OXIDE